Poiseuilleförhållandet

Poiseuilleförhållandet, also known as Poiseuille's law, is a fundamental principle in fluid dynamics that describes the flow of a viscous fluid through a cylindrical pipe. It was formulated by Jean Louis Marie Poiseuille in 1840. The law states that the volume flow rate Q of the fluid is directly proportional to the pressure difference ΔP across the pipe and the fourth power of the pipe's radius r, and inversely proportional to the fluid's viscosity μ and the length L of the pipe. Mathematically, this relationship is expressed as:

Q = (π * ΔP * r^4) / (8 * μ * L)

where:

- Q is the volume flow rate,

- ΔP is the pressure difference,

- r is the radius of the pipe,

- μ is the dynamic viscosity of the fluid,

- L is the length of the pipe.

Poiseuille's law is applicable to laminar flow, where the fluid flows in parallel layers without mixing. It is widely used in various fields, including physiology, where it helps explain blood flow in capillaries, and engineering, where it aids in the design of fluid transport systems. The law also has implications for understanding the behavior of fluids in biological systems and industrial processes.